Odd bitsetting question

Looking for some advice on how to implement a strange bitsetting situation. I
have an older custom logging software/hardware that rejects using dvd+rw media in a burner. I need to be able to use +rw media in the drive and the drive is +rw capable.

Is it possible to report back to an app that a dvd+rw is a dvd+r but the drive still needs to be able to implement it’s normal +rw strategy. The bitsetting is to fool the app BEFORE the writing takes place.

I have an older nd-4551a drive that I am willing to experiment with. Is it possible to ‘fool’ the media table? Or does this require a patched firmware for the drive? Any tips or guidance? Or am I missing something very very basic?

Regards all.

I’m not 100% sure if that’s possible at all. This would require all commands for writing a disc to be the same on both type of discs. I think there are differences between plus and minus and there may also be one between R and RW.

Even if the commands are the same you would need to patch a firmware to report a disc as DVD+R everytime a DVD+RW is inserted. While this should not be impossible, it would probably require quite an ammount of work finding and changing the relevant code.

Thanks for the reply. I guess I can hook up an analyzer to the flash firmware and watch the IDE interface for the relevant commands and see whats going on. The NEC chipset used in the 4550 series is still v850e1 core, right? A upd63645/3345 combo? Maybe I can chase a door open sensor to an int. vector. Just not sure what happens when yo u get a media change. I know there will be a lot of focus/servo retraining – but I think the only real change might be laser write current baselines. Hmm. I just need it to work with one media type and a single strategy. Anybody ever dig up any released info on the chipset? Regards.

The 4550 series indeed uses a V850 core. As far as I remember, you would probably have to patch the GetConfiguration command (cdb[0]=0x46). So it lists DVD+R as current profile although there’s a DVD+RW in the drive. You should be able to leave everything else untouched as it’s only what the drive reports back to the PC that needs to be changed.
If you tell me which firmware you’d like to patch, I should be able to tell you the entry point for the GetConfiguration command and also which address is used to distinguish between different disc types - probably even which value DVD+R and DVD+RW have.

Might as well use your nd4551 1-09 release. It’s certainly worth a try. Sounds like a plan. I’ll just patch the return and see what happens…I really appreciate your help. Regards

The firmware starts at 0x10000
The GetConfiguration routine starts at 0x107ea4 in firmware 1-09
80[ep] - 88[ep] are cdb[0] to cdb[8]
ld.b -29499[gp],rXX will load the current disctype to register rXX (could also be 0x8CC5 instead of -29499 depending on what the disassembler shows) with 80 (0x50) meaning DVD+R and 81 (0x51) meaning DVD+RW (82 would be DVD+R-DL)
The instructions starting at 0x107cd0 look interesting on first sight but I don’t have time to check in detail